Why does PayPal (One Click Upsells) force customers to have a PayPal account rather than allowing to check out as a guest?

I set up the Paypal 1 click upsell. But when I tested it, it forced me to make a Paypal account rather than checking out as a guest (see attached).  How do I make it so that Paypal 1 click upsell does not go through a forced Paypal account?

Your customers have to have a PayPal account so that you can be able to charge them in a true One Click way.

It happens because on checkout PayPal creates a so called Reference between your merchant account and customer’s account for future payments, which allows One Click Upsells to be charged properly.